Magnetic Eraser?

Hi,
My friend and I were arguing about this the other day and I wanted some input from you guys:

How many teslas would it take to potentially harm a computer. In the lab we use a .155Tesla magnet to move encased objects around in our rutherford scattering lab. I said that the magnet was not nearlly strong enough to harm a computer even if you put it right on its caseing. He said that even small magnets like fridge magnets could potentially harm a computer if waved around the caseing. He said the induced current would damage transformers. I differed saying that the induced current would be much to small and would have little effect even from the bigger 0.155 tesla magnet we were using.

1) Computers don't have many transformers. The power supply has at least one, but that's about it.

2) The induced currents caused by waving a magnet at a computer are incredibly tiny, and all modern integrated circuits have protection networks that can withstand kilovolts without damage. No problem there.

3) Hard disk drives and other media are vulnerable only to very high flux density magnetic fields, and only in certain orientations. The read/write head in a disk drive is very small and very very close to the disk surface, enabling it to create very high flux densities when writing. You'd have to get your magnet extremely close to the disk to create any real threat.

4) Finally, the most sensitive components in a computer are heavily shielded, and you'll just be inducing currents on the outside of the shield material.